Motion transforming device for producing a reciprocating motion

ABSTRACT

The catch sprocket is driven in an endless path by the upper chain of the double chain while the lower chain is driven about the two drive sprockets. When the motion direction is reversed, the catch sprocket is moved at a curved end of the endless chains from one guide slot to the other. The travel-to-time curve of the catch sprocket can be shaped in any suitable manner while the reversing time remains of short duration.

United States Patent [151 3,673,876

Rohner July 4, 1972 541 MOTION TRANSFORMING DEVICE 2,821,861 2/1958 Dunn3/4 30 FOR PRODUCING A 3,273,408 9/1966 Nagel et a1 ..74/37 FOREIGNPATENTS OR APPLICATIONS [72] Inventor: Friedbert R. Rohner,Kukenthalstrasse 898,518 7/1944 France ..74/37 12a, Coburg, Bavaria,8630, Germany I Primary Examiner-William F. ODea [22] Flled Sept 1970Assistant Examiner-Wesley S. Ratliff, Jr. [21 Appl. No.: 73,783Attorney-Kenyon & Kenyon Reilly Carr & Chapin l P [57] ABSTRACT 30 F A lI D (a l 1 Drug" pp ca m "on y a The catch sprocket is driven in anendless path by the upper I969 Germany I9 53 9-5 chain of the doublechain while the lower chain is driven about y 2 y 757-3 the two drivesprockets. When the motion direction is [52] v "74/37 reversed, thecatch sprocket is moved at a curved end of the [51] In C 19/06 endlesschains from one guide slot to the other. The travel-to- 58} Field 74/37time curve of the catch sprocket can be shaped in any suitable mannerwhile the reversing time remains of Short duration.

[56] References Cited 9 Claims, 7 Drawing Figures UNITED STATES PATENTS2,309,578 1/1943 Drachman ..74/37 v! I rim IllIIII/ l PATENTEDJUL 4 I9723,673,876

sum 3 or 3 INVENTOR.

FRIEDaERT FR. QQHNER MOTION TRANSFORMING DEVICE FOR PRODUCING ARECIPROCATING MOTION This invention relates to a motion transformingdevice for producing a reciprocating motion.

In many fields of technology, a rectilinear motion with a constantabsolute value of the velocity is required. Further, if the availablecourse for the motion is to be used more than once, a reversal of thedirection of the moving parts becomes necessary. Such a reversal,however, should be carried out over a course with a duration as short aspossible while the velocity is reversed from +v to v. The more rapidthis reversal of the direction is accomplished, the greater are thecorresponding accelerations.

Up to the present time, various motion transforming devices have beenknown which have used cams, reversing screwshafts or chainorbeltdrivings with fastened catches as driving elements in order toprovide for a reversal of a driven part in a reciprocating path.However, with all of these arrangements, such high loads have beenproduced on the transferring parts at the places of reversal in spite ofthe relative slow speed of reversal, that the wear of these parts hasled to breakdowns.

Accordingly, it is an object of the invention to effect a reversal of areciprocating part with a minimum of wear.

It is another object of the invention to effect a reversal of areciprocating part in an extremely short period of time.

It is another object of the invention to increase the stability of amotion transforming device at the places of reversal of a driven part.

Briefly, the invention provides a motion transforming device forproducing a reciprocating motion. The device utilizes a multiple chainwhich has one chain which meshes with a pair of sprockets in order to bedriven thereby while a second chain is carried alone in unencumberedfashion. In addition, a catch sprocket is disposed within the secondchain in selective meshing engagement with only one of the reaches ofthe chain at a time in order to transfer a reciprocating motion to aslider within a fixed guide. To this end, the catch sprocketis sized andguided within a suitable guide means so as to move with the intermeshedreach of the second chain.

In order to reverse the direction of movement of the slider, the catchsprocket is guided by the guide means away from the first reach intomeshing engagement with the second reach of the chain at the ends of therespective reaches. The catch sprocket is also provided with slidepieces which permit the catch sprocket to move between the reaches ofthe chain of the multiple chain as well as within the slider withoutrotation during this reversing course. In this way, the catch sprocketis prevented from rotating with respect to the slider while beingreversed in direction.

The path which the catch sprocket is driven through can be defined byany suitable endless path consonant with the function of the slider. Forexample, the catch sprocket, as defined by the centerlinc, can follow anelongated oval shaped path with parallel runs; a path in which one runis inclined with respect to the other; and a path in which one run isformed of two portions in angular relation to each other.

These and other objects and advantages of the invention will become moreapparent from the following detailed description and appended claimstaken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a plan view of a motion transforming device accordingto the invention;

FIG. 2 illustrates a fragmentary side view of the device of FIG. 1;

FIG. 3 illustrates an end view and a side view, respectively of a catchsprocket according to this invention;

FIG. 4 illustrates a line of travel of the center of the catch sprocket,and a travel time graph;

FIG. 5 illustrates alternate lines of travel of the center of the catchsprocket with associated travel time graphs;

FIG. 6 illustrates an end view and a side view, respectively, of anotherembodiment of the catch sprocket according to the invention; and

FIG. 7 illustrates a view of the catch sprocket at a point of reversal.

Referring to FIGS. 1 and 2, the drive transforming motion, e.g., for athread guide (not shown) of a winding machine, includes a double chain 1which has a lower chain and an upper chain. The lower chain extendsbetween'and around two single sprockets 2, 3 one of which drives thechain 1. The

sprockets 2, 3 mesh with the lower chain only and do not, at any oneposition, obstruct the run of the upper chain. The total length of theupper chain is thus freely accessible from the inside. The transformingmotion also has a slider 5 which is slidably mounted in a fixed guide 4positioned over the chain and which is driven in a reciprocating motion.

In order to transmit a reciprocating motion to the slider 5 from thechain 1, a circular catch sprocket 6 is connected between the chain 1and slider 5. This catch sprocket 6 has a diameter which is less thanthat of the sprockets 2 and 3 so as to be in meshing engagement withonly one of the reaches of the upper chain at a time. Also, the catchsprocket 6 is provided on the upper face with an elongated slide piece 7which engages in a guide groove 8 of the slider 5 and on the lower facewith a slide piece 9 which extends perpendicularly to the upper slidepiece 7. As shown in FIG. 3, the slide pieces 7, 9 are turned withrespect to each other. In addition, a guide means for guiding the catchsprocket 6 is an endless path is located a short distance above thesprockets 2, 3. This guide means includes a guide plate 10 which has twoparallel slots ll, 12 in which the slide piece 9 of the catch sprocket 6is alternately received.

The guide plate 10 also has a web 13 separating the slots ll, 12 whichis only slightly longer than the distance between the sprockets 2, 3.

In operation, the catch sprocket 6 is mounted with the slide piece 9 ina slot 11, 12. of the guide plate 10 and with the slide piece 7 in thegroove 8 of the slider 5. The teeth of the sprocket 6 to one side arealso disposed in meshing engagement with one reach of the upper chain.Because of the slide piece 7, the catch sprocket 6 is not able to rotatein the slider 5. As a result, when the rectilinear reach of the upperchain is in motion, the chain conveys the catch sprocket 6 via the teethso as to slide by means of the slide piece 9 in the slot 12. The slidepiece 9 also ensures proper meshing of the teeth and simultaneouslyprevents engagement with the chain on the opposite side. Shortly beforethe reversing point at the left, as viewed, the slide piece 9 leaves theslot 12 and the catch sprocket 6 then passes along the semicircular turnof the chain 1, until the side of meshing has changed. That is, as shownin FIG. 7, the slide piece 9 and catch sprocket 6 are sized so that whenthe slide piece 9 emerges out of the slot 12 a forward tooth C becomesmeshed with the chain 1. The catch sprocket 6 is then carried by thechain 1 in a direction generally perpendicular to the axes of the slots11, 12 until the slide piece 9 becomes aligned with the slot 12. At thistime, a tooth B comes into meshing engagement with the chain 1 while atooth A simultaneously comes out of meshing engagement with the chain 1.Thus, an extremely short reversal of the catch sprocket 6 is attained atthe points of reversal since the catch sprocket 6 moves into meshingengagement with the oppositely running chain piece immediately afterleaving the other chain piece. During this time the slide piece 7 movesa small distance in the guide groove 8. The advance in the oppositedirection under the influence of the chain then causes the lower slidepiece 9 to enter the slot 11 and, therefore, to lock the teeth intomeshing engagement with the chain. Shortly before the reversing point atthe right as viewed, the slide piece 9 again leaves the slot 11whereupon in an analogous way a subsequent reversal and a new advancetake place until the starting position is again reached.

During the reversal of the catch sprocket 6 wherein the chain links arepassed between the teeth A and B an increase in speed is attained. Forexample, if the lower chain sprocket 2 has 14 teeth and the catchsprocket 6 has 10 teeth, the semicircular reversal takes place over alength equal to two pitches of the chain as determined by the expressionV (Z,/2 ZJZ) wherein V is the speed of the chain 1 and Z the respectivenumber of teeth in the sprockets 2, 6. Consequently, at each reversalthe catch sprocket 6 overtakes five pitches of the chain l so that ineach straight chain piece, the catch sprocket 6 is sequentiallypositioned five pitches forward. The reversal of the sprocket thus takesplace over an arcuate distance of 51.4" as determined by the expression(2, ZJZ,) X 180.

The smaller the difference is between the diameters of the catchsprocket 6 and the sprockets 2 and 3, the more rapid the reversal ofdirection is produced. While this results in increased accelerationforces, the plane of contact between the catch sprocket 6 and the chain1 is also increased. Since the diameters of the sprockets, 2, 3 have noinfluence on the reversing time, the chain remains very stable.

The center of the catch sprocket 6 remains a constant distance from thecenterline of the chain 1 and follows a line of travel as shown in FIG.4, consisting of two straight portions l4, l5 and two circular portions16, 17 with the distance between the straight portions l4, being equalto the diameter of the circular return bend. The smallest possibledistance is about equal to the depth of the teeth of the catch sprocket6. From the foregoing, the travel time graph illustrated is induced withthe desired reversing times of short duration.

By properly selecting the elements concerned, a great number of lines oftravel may be established. Some of the possible lines of travel of thecenter of the catch sprocket with the associated travel time graphs areillustrated in FIG. 5. For example, the slots of the guide plate can bedisposed in angular relation with the sprockets 2, 3 being made ofdifferent diameters so as to produce a line of travel as shown. Also,one slot of the guide plate can be formed with two portions which are inangled relation to each other. Further, both slots of the guide platecan be angled as indicated in the lower part of FIG. 5 with thesprockets 2, 3 being made of different diameters.

Referring to FIG. 6, the catch sprocket 60 can alternatively be providedwith a longitudinally elongated form in order to decrease the distancetravelled by the slider 5.

It is noted that the catch sprocket 6 does not rotate when passing fromone slot to the other of the slots l1, 12. In addition, very highfrequencies of reversal can be obtained since a number of teeth of thecatch sprocket 6 are caught within the chain 1 especially at thereversal points so that the reversing forces due to inertia can bereceived efi'ectively.

What is claimed is: l. A motion transforming device for producing areciprocating motion comprising a multiple chain having at least twochains; a pair of sprockets in meshing engagement with one of saidchains for driving said chains; a catch sprocket having a plurality ofteeth thereon, at least one of said teeth being in meshing engagementwith a selective one of a pair of reaches of the other of said chains; I

guide means for guiding said catch sprocket in an endless path inselective meshing engagement with said reaches of said other chain, saidcatch sprocket being slidably received in said guide means and sized tomesh one of said teeth in an oppositely moving reach of said' otherchain while another of said teeth disengages'from the other of saidreaches; and

a slider connected to said catch sprocket for reciprocating in arectilinear path upon movement of said catch sprocket in said endlesspath.

2. A motion transforming device as set forth in claim 1 wherein saidguide means includes a guide plate having a pair of slots therein andsaid catch sprocket includes a first slide piece on one side thereofslidably received in a selective one of said slots for guiding of saidcatch sprocket therein during movement in said endless path.

3. A motion transforming device as set forth in claim 2 wherein saidslider has a groove therein and said catch sprocket has a second slidepiece slidably received in sard groove to prevent rotation of said catchsprocket relative to said slider, said second slide piece being turnedwith respect to said first slide piece to permit movement of said catchsprocket in two directions perpendicular to each other.

4. A motion transforming device as set forth in claim 2 wherein saidslots are parallel to each other.

5. A motion transfonning device as set forth in claim 2 wherein saidslots are angled with respect to each other.

6. A motion transforming device as set forth in claim 2 wherein one ofsaid slots has two portions disposed in angular relation to each other.

7. A motion transforming device as set forth in claim 1 which furthercomprises a fixed guide slidably receiving said slider therein forreciprocation therein.

8. A motion transforming device as set forth in claim 1 wherein saidcatch sprocket is circular.

9. A motion transforming device as set forth in claim 1 wherein saidcatch sprocket has a longitudinally elongated form to decrease thedistance travelled by the slider.

1. A motion transforming device for producing a reciprocating motioncomprising a multiple chain having at least two chains; a pair ofsprockets in meshing engagement with one of said chains for driving saidchains; a catch sprocket having a plurality of teeth thereon, at leastone of said teeth being in meshing engagement with a selective one of apair of reaches of the other of said chains; guide means for guidingsaid catch sprocket in an endless path in selective meshing engagementwith said reaches of said other chain, said catch sprocket beingslidably received in said guide means and sized to mesh one of saidteeth in an oppositely moving reach of said other chain while another ofsaid teeth disengages from the other of said reaches; and a sliderconnected to said catch sprocket for reciprocating in a rectilinear pathupon movement of said catch sprocket in said endless path.
 2. A motiontransforming device as set forth in claim 1 wherein said guide meansincludes a guide plate having a pair of slots therein and said catchsprocket includes a first slide piece on one side thereof slidablyreceived in a selective one of said slots for guiding of said catchsprocket therein during movement in said endless path.
 3. A motiontransforming device as set forth in claim 2 wherein said slider has agroove therein and said catch sprocket has a second slide piece slidablyreceived in said groove to prevent rotation of said catch sprocketrelative to said slider, said second slide piece being turned 90* withrespect to said first slide piece to permit movement of said catchsprocket in two directions perpendicular to each other.
 4. A motiontransforming device as set forth in claim 2 wherein said slots areparallel to each other.
 5. A motion transforming device as set forth inclaim 2 wherein said slots are angled with respect to each other.
 6. Amotion transforming device as set forth in claim 2 wherein one of saidslots has two portions disposed in angular relation to each other.
 7. Amotion transforming device as set forth in claim 1 which furthercomprises a fixed guide slidably receiving said slider therein forreciprocation therein.
 8. A motion transforming device as set forth inclaim 1 wherein said catch sprocket is circular.
 9. A motiontransforming device as set forth in claim 1 wherein said catch sprockethas a longitudinally elongated form to decrease the distance travelledby the slider.